Sex Hereditary Determination Essay Research Paper Concerns

Sex Hereditary Determination Essay, Research Paper Concerns the determination of the gonads. In mammals, determination strictly chromosomal; not influenced by the environment. Most cases- female = XX; male=

Sex Hereditary Determination Essay, Research Paper

Concerns the determination of the gonads. In mammals, determination strictly

chromosomal; not influenced by the environment. Most cases- female = XX; male=

XY Every individual organism has atleast one X Chromosome. Since the female has

2 X chromosomes, each of her eggs posses one X chromosome. The male posses an X

and a Y, so therefore the male can produce 2 kinds of sperm, one with an X

chromosome and one with a Y chromosome. If an offspring receives an X and a Y,

then it will be a male. TheY chromosome carries a gene that encodes a testis

determining factor. If a person had an innumerable number of x chromosomes and

one y chromosome, they would be male. If a person is born with only a single x

chromosome and no second x or y, then they develop as a female, but are

infertile.(not able to maintain ovarian follicles) More Primary Sex

Determination- In the is absence of the Y chromosome , the primordial gonad body

develops into ovaries. the ovary then produces the estrogenic hormones, which

contains estrogen and other such hormones, enabling the development of the

Mullerian duct into the uterus, fallopian tubes, and upper end of the vagina. In

the presence of Y chromosome, the testes form. The testes secrete two major

enzymes. The first hormone, AMH(anti-Mulllerian duct hormone), destroys to

Mullerian duct. The second, testosterone, stimulates the masculinization of the

fetus. During this process the penis, scrotum, and other male anatomical

structures form. The development of the primordial breast is inhibited. The

body, therefore, has the female phenotype unless it is altered by two hormones

created in the fetal testes. The development of gonads is the only fetal organ

development process that has the chance of developing into more than one organ

(under normal circumstances and barring mutations). The primordial gonad can

develop into either an ovary or a testis. Before the gonad develops into the

testes or ovary, it first goes through an indifferent stage, also known as a

bipotential stage, during which time it has neither male or female

characteristics. In humans, the primordial gonad first develops in the 4th week

and remains indifferent until the 7th week. Sex Determinant genes- In humans,

the major genes for the testis determining factor reside on the short arm of the

Y chromosome. Individuals born with the short arm of the Y chromosome, but not

the long are males. Those born with the long end but not the short are actually

female. Through scientific research on XX males and XY females, the position of

the testis-determining gene has been narrowed down to a small region. On the

short arm of the Y chromosome there is believed to be an area called the HMG

box, which stands for high-mobility group box. This HMG box is believed to

contain the genetic information to establish masculinity. There are two known

major genes in this HMG box that are believed to have an effect on the

determining of sex, SRY and SOX9. SRY (sex-determining region of the Y) is found

in XY males, is absent from XX females, is found in the rare XX males, and is

absent in the XY females. Many XY women were found to have a point mutation in

the SRY gene, which would prevent the SRY protein from binding to the DNA. Since

humans are difficult to study, Scientists found a different way to study this

gene. In mice, there is a gene homologous to SRY, which is named Sry. the mouse

gene also correlates with the presence of testes; it is present in XX males and

absent in XY females. To further test this theory of Sry being the testes